Plasmaron excitations in p(2x2)-K/Graphite

A new type of plasmarons formed by the compound of photoelectrons and acoustic surface plasmon excitations is investigated in the system p(2x2)-K/Graphite. The physics behind these types of plasmarons, e-plasmarons, is different from the ones recently found in graphene where the loss feature is argued to result from the photohole-plasmon interaction, h-plasmarons. Based on first principles methods we calculate the dispersion of e-plasmaron excitation rate which yields a broad feature below the parabolic quantum-well band with a peak about 0.4 eV below the quantum well band in the Gamma-point.